armfly/User/app/avltree/avltree.h

#ifndef __AVL_TREE_H__
#define __AVL_TREE_H__

//------------------------------------------------------------------
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) & ((TYPE *)0)->MEMBER) // 获取"MEMBER成员"在"结构体TYPE"中的位置偏移
#endif

#ifndef container_of
#if 1
// 根据"结构体(type)变量"中的"域成员变量(member)的指针(ptr)"来获取指向整个结构体变量的指针
#define container_of(ptr, type, member) ((type *)((char *)ptr - offsetof(type, member)))
// 此宏定义原文为 GNU C 所写，如下，有些编译器只支持 ANSI C /C99 的，所以作以上修改
#else
#define container_of(ptr, type, member) ({          \
		const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
		(type *)( (char *)__mptr - offsetof(type,member) ); })
#endif
#endif
//------------------------------------------------------------------

struct avl_node
{
    unsigned long    avl_parent;
    struct avl_node *avl_left;
    struct avl_node *avl_right;
};

struct avl_root
{
    struct avl_node *avl_node;
};

#define avl_parent(r) ((struct avl_node *)((r)->avl_parent & (~3)))

//------------------------------------------------------------------
// 获取 avl 节点的平衡因子，值如下
#define avl_scale(r)   ((r)->avl_parent & 3)
#define AVL_BALANCED   0 // 节点平衡
#define AVL_TILT_RIGHT 1 // 节点右边比左边高，用 0b01 表示，右倾
#define AVL_TILT_LEFT  2 // 节点左边比右边高，用 0b10 表示，左倾

//------------------------------------------------------------------
// 设置 avl 节点的平衡因子
// 设置 avl 节点为平衡节点
#define avl_set_balanced(r)        \
    do                             \
    {                              \
        ((r)->avl_parent) &= (~3); \
    } while (0)

// 设置 avl 节点为右倾节点
#define avl_set_tilt_right(r)                                        \
    do                                                               \
    {                                                                \
        (r)->avl_parent = (((r)->avl_parent & ~3) | AVL_TILT_RIGHT); \
    } while (0)

// 设置 avl 节点为左倾节点
#define avl_set_tilt_left(r)                                        \
    do                                                              \
    {                                                               \
        (r)->avl_parent = (((r)->avl_parent & ~3) | AVL_TILT_LEFT); \
    } while (0)

//------------------------------------------------------------------

#define avl_entry(ptr, type, member) container_of(ptr, type, member)

// 设置 avl 节点的父节点为 p
static inline void avl_set_parent(struct avl_node *avl, struct avl_node *p)
{
    avl->avl_parent = (avl->avl_parent & 3) | (unsigned long)p;
}

void avl_insert(
    struct avl_root  *root,
    struct avl_node  *insertnode,
    struct avl_node  *insertparent,
    struct avl_node **avl_link);

void avl_delete(struct avl_root *root, struct avl_node *node);

/* Find logical next and previous nodes in a tree */
extern struct avl_node *avl_next(const struct avl_node *);
extern struct avl_node *avl_prev(const struct avl_node *);
extern struct avl_node *avl_first(const struct avl_root *);
extern struct avl_node *avl_last(const struct avl_root *);
void                    avl_replace_node(struct avl_node *victim, struct avl_node *new,
                                         struct avl_root *root);
#endif